manager: keep device if realize() fails

system_create_virtual_device() first creates the device (unrealized)
and then, if there a connection for the device with autoconnect=yes,
creates the backing resources. If this last step fails the device
should continue to exist, even if in an unrealized state.
17 jobs for bg/device-realize-failed-rh1686634 in 40 minutes and 22 seconds (queued for 2 seconds)